Holder for impact tools



Patented June 9, 1942 HOLDER FOR IMPACT TOOLS Matthew OFarrell, Detroit, Mich.,

Chicago Pneumatic Tool Company,

assigner to New York,

N. Y., a corporation of New Jersey l Application June 29, 1940, Serial No. 343,077

(Cl. 21S-19.3)

Claims.

This invention relates generally to means for controlling movement of the Working implement of a percussive tool and more particularly to a retaining ring combining the functions of a steel retainer and steel puller, and adapted to be mounted within the front end of a conventional rock drill.

The retaining ring of the invention is particularly adapted for use with flat, rectangular broaching steels used to cut away the wall of rock lying between adjacent drill holes. The ring is adjustable relatively to the steel and to the tool body and is settable to a plurality of positions, to permit insertion of the breaching steel into the tool in a plurality of rotative positions with respect to the tool, and, to prevent Withdrawal of the steel from the tool.

One object of the invention is to embody within the front end of a conventional percussive tool a retaining ring combining the functions of a steel retainer and steel puller, adapted for use with broaching steels.

Another object of the inventio-n is to enable the broaching steel to be released from the steel retaining means without the necessity of twisting the steel relatively to the tool.

Another object of the invention is to obtain a rugged, simple and enclosed steel pulling means for a broaching steel.

Other objects and structural details of the invention will be apparent from the following description when read in conjunction with the accompanying drawings, wherein:

Fig. 1 is a view, in longitudinal section, of the front end of va percussive tool embodying the mechanism of the invention, with parts of the breaching steel broken away and the retaining ring shown in releasing position;

Fig. 2 is a view, in longitudinal section, of the front end of a conventional rock drill;

Fig. 3 is an end view of the tool shown in Fig. l, the broaching steel being shown in cross section and partly broken away to show an engaging shoulder thereof;

Fig. 4 is a view similar to Fig. 3, showing the retaining ring adjusted to locking position;

Fig. 5 is a view, in cross section, of the front head and broaching steel and is taken substantially along the line 5-5 of Fig. 1;

Fig. 6 is a detail view of the closure plate secured to the outer end of the front head, a portion of the plate being broken away to show a detent plunger mounted therein;

Fig. '7 is a View, in cross section, of the closure with the piston 25.

plate and is taken substantially along the line 1 1 of Fig. 6;

Fig'. 8 is a detail view of the retaining ring, a. portion of the ring being broken away to show a pair of detent notches formed therein;

Fig. 9 is a view, in cross section, of the retaining ring and is taken substantially along the line 9--9 of Fig. 8;

Fig. 10 is a view, in longitudinal section, of the tool shown in Fig. l and is taken substantially along the line Ill-I0 of Fig. 1;

Fig. l1 is a plan view showing the breaching steel in cross section with its outer end in engagement with the rock; and

Fig. 12 is a view, similar to Fig. 9, of a modified retaining ring.

As shown in Figs. 1 and 2, the stationary and supporting elements of the front end of the percussive tool herein illustrated include a cylinder l5, a cylinder bushing I6 and a cylinder extension or front head l1 secured to the cylinder I5 by means of side bolts IB. A closure plate, constructed as the one indicated at I9 in Fig. 1, or as the one indicated at 2l in Fig. 2, closes the iront end of extension I1 and is secured thereto by means of bolts 22 passed through aligned holes formed in ear-like projections 23 on the closure plate andsimilar projections 24 on the front end of the extension. A hammer piston 25 reciprocates within the cylinder I5 and there is supported within the cylinder, and extension I1 thereof, certain motion transmitting and chuck elements, interchangeable in order that the tool easily adapted for use as a rock drill or broaching tool. The chuck elements are held within the tool by the closure plate which must be removed to permit Withdrawal and replacement of the elements.

In Fig. 2, the tool is shown adapted for use as a rock drill. In this construction, the interchangeable elements within the front end of the tool comprise a chuck 26, a chuck sleeve 21 and a chuck nut 28 xed within the rear end of the chuck sleeve and having a splined connection The adjacent ends of the chuck 26 and sleeve 21 are formed with interengaging portions whereby rotation of one of these elements effects a corresponding movement of the other. Rotation mechanism (not shown) imparts a step-by-step rotary motion to the piston 25, during operation of the tool, and this motion is transmitted through the chuck nut 23 to the sleeve 21 and chuck 26. A drill steel 29 is inserted into the tool, through an opening 3l may be in the closure plate 2|, and is arranged with its v inner end in position to receive impacts from the hammer piston 25. A bushing 32 serves as a mounting for the steel 29 while a plurality of lugs 33 on the steel engage ribs on the chuck 26 and cause the steel to rotate with the chuck.

The structure of Fig. 2 is that of a conventional form of rock drill. In adapting such a structure for use as a broaching tool the chuck 26 is replaced by a chuck 34 (Fig. 1) having a flange 35, at its front end, positioned in a counterbore formed in the outer extremity of the extension I1. The chuck sleeve 21 is replaced by a sleeve 36 (Fig. 1) having no interengagement with the chuck 34. The chuck nut 28 is omitted from the broaching construction and there is no driven movement of the chuck and chuck sleeve, although both elements are movable within the tool. The chuck 34 is formed, throughout its length, with a rectangular opening 31 adapted to receive the similarly shaped shank of a broaching steel 33 (see also Fig. Also formed in the chuck 34 is a central bore 39 which terminates at the rear of the chuck in a counterbore or recess 4|. In assembling the tool, the steel 38 is inserted through an opening 42 in closure plate I9 into the rectangular opening 31 and moved rearwardly until its inner end lies within the recess 4|. When so positioned, the steel engages the head 43 of an anvil block 44 which transmits impacts to the steel 4from the hammer piston 25. The chuck sleeve 36 acts as a bushing for the anvil block 44 while the recess 4| provides a clearance space around the head 43, of the block.

The closure plate I9 Vis formed with an inwardly extending ilange 45 (Figs. 1 and '7) which engages the flange 35 of chuck 34 to hold the chuck elements and anvil block 44 in position within the tool. For the purpose of holding the broaching steel 38 within the tool there is provided a retaining ring 46 (Figs. 1, 8 and 9) seated in a counterbore 41 formed in the inner surface of the plate I9. A centra-l bore 43 in the ring 46 is of a diameter less than the width of the steel 38 and there is formed in the inner periphery of the ring two intersecting slots 49 and 5I (see Fig. 8) disposed at right angles to each other and cut to a sufficient depth to enable the broaching steel to be inserted therein and passed through the ring into the tool. When inserted in the tool, the broaching steel normally lies with a reduced neck-like portion 52 thereof (Fig. 1) adjacent the retaining ring 46. The reduced portion 52 of the steel is suciently narrow to pass through any part of the central bore 48, in the ring 46, and so the steel may be moved freely between the limits dened by the shoulders 53 and 54 connecting reduced portion 52 to the main body of the steel. Forward movement of the steel is limited by engagement of the rearward set of shoulders 53 with theprojecting portions of the ring 46, lying between the slots 49 and 5|. Rearward movement of the steel may be limited by engagement of the forward set of shoulders 54 with the ring 46, or by engagement of the inner end of the steel with the anvil block 44. The retaining ring 46 is adjustable within the closure plate I9 to move the slots 49 and 5| into and out of registry with the shoulders 53 to permit and prevent free kmovement of the broaching steel in and out of the tool. To facilitate adjustment of the retaining ring it is formed with a pair of lugs 55 which, as shown in Figs. 3 and 10, extend forwardly through respective slots Y56, in plate I9,

and may be grasped manually to turn the ring relatively to the plate. Rotation of the retaining ring is limited to the length of the slots 56, which allow the ring a movement of approximately 45 degrees from one extreme position, shown in Fig. 3, to the other extreme position, shown in Fig. 4. As shown in Figs. 6 and. 7, a spring pressed detent plunger 51 is mounted in the closure plate I9 and projects into the counterbore 41 where it may engage one or another of a pair of detent notches 58 (see Fig. 8), in the retaining ring 46, to hold the ring yieldingly in either of its extreme limits of movement.

Preparatory to inserting the broaching steel into the tool, the retaining ring 46 is set to the position shown in Fig. 3 and the chuck 34 is adjusted to align the rectangular slot 31 therein with one or another of the slots 49 and 5I, according to whether the steel is to be used to cut along a line parallel to the side bolts I8 and 22 or along a line at right angles to the side bolts. The steel is then inserted through the selected one of the vslots 49 and 5| and is moved rearwardly in the tool until the set of shoulders 53, marking the rear of reduced portion 52, passes beyond the retaining ring 46. At this point the ring 46 may be turned in a clockwise Vdirection (Fig. 3) to the position shown in Fig. 4 to place the slots 49 and 5| out of cooperative relation with the shoulders 53 and thereby lock the broaching steel within the tool.

It will be evident that modifications may be made in the construction of the retaining ring 46 and closure plate I9 without departure from the spirit of the invention. For example, 'it is not essential that rotary movement of the retaining ring be positively limited, and accordingly the closure plate I9 may be constructed without the limit slots 56. If the arcuate slots 56 are omitted (or in effect extended around the entire circumference) the retaining ring may be turned to any desired position relatively to the closure plate. Such a modified retainer ring is illustrated in Fig. 12. This ring 46a is formed with but one slot 5Ia in its inner periphery as compared with the two slots 49 and 5I of the Fig. 9 embodiment. Slot 5|a is settable at will to a position parallel to or at right angles to the plane of the side bolts I8 and 22. In such a construction the retaining ring 46a is preferably formed with a series of detent notches 58a corresponding to notches 58 but spaced 45 degrees apart around its entire outer periphery. It will further be evident that the lugs 55 may be replaced by an outwardly projecting sleeve or ilange 55a occupying all vor any part of the circumference of the retaining ring. The sleeve may be Vturned by a tool inserted .through holes 55o.

Should the tool be operated with the broaching steel not iny contact with the work, a blow is delivered between shoulders 53 and ring 45 and is transmitted to the closure plate I9 and to the bolts 22, securing the closure plate to the cylinder extension I1. The force of the blow is absorbed by a pair of compression springs 59 (Fig. 1) each cf which surrounds a rearwardly extending portion of a respective bolt 22 and is interposed between a projection 24 and a nut 6I, fixed to the inner end of the bolt.

It will be observed that the retaining ring 45 functions both as a steel retainer and as a pulling means for withdrawing the steel from the work. This construction renders unnecessary the provision of special steel pulling attachments, such as grab hooks and the like, dependent from the outer surface of the cylinder. It will also be noted that when inserting the steel into the tool or withdrawing it therefrom it is not necessary to twist the steel out of the plane of the cutting line, nor is it necessary to turn the entire tool when inserting or withdrawing the steel.

This feature is of particular importance when the tool is used in quarry work to cut out the sections of rock lying between a series of drill holes. In this work, a rock drill, such as the one shown in Fig. 2, is used to drill a series of holes defining, in outline, the block of material, such as stone, granite, or the like, to be removed. One corner of a block so defined is shown in Fig. l1, wherein the drill holes are indicated at A. A wall of uncut material lies between each pair of holes A and this wall is cut away by a breaching steel which, as it is driven forwardly, produces a channel B between adjacent holes A. When making deep cuts it is advisable periodically to replace one steel with another of a greater length. To withdraw a steel from the tool for this purpose the entire tool body may be moved away from the work a sufficient distance to pull the steel out of the channel B. A more desirable manner of working, however, is to retract the tool only through the relatively short distance necessary to enable the steel to be pulled forwardly out of the tool and then withdrawn by hand from the channel. The channel B is of the same generally rectangular shape as the broaching steel and so prevents any substantial amount of turning or twisting of the steel relative to the channel. For this reason disengagement of the steel from the tool cannot be effected by twisting the steel, while it is within the channel, and it is frequently impractical to turn the entire drill. The retaining ring 46, which Amay be adjusted to releasing or locking position independently of the tool body and breaching steel, has thus a particularly useful application in broaching operations of this type.

Referring again to Fig. 11, it will be seen that in following the series of drill holes A the breaching steel is applied to the work in one position when cutting along a horizontal line of drill holes and in a second position, at right angles to the rst position, when cutting along a vertical line of drill holes. This change in position of the breaching steel is made by withdrawing the steel from the work, and from the tool, and reinserting it in the tool through the other of the slots 49 or 5l, in ring 46.

What is claimed is: j

l. In a device of the class described, the combination of a front head, a closure plate secured to the outer end of said front head, a working implement movable within said front head and extensible through said closure plate, means supported by said closure plate and movable relatively thereto for controlling movement of said working implement within said front head, and a projection on said means cooperative with said closure place to restrict said means to an' oscillating movement between positive limits defined by said closure plate.

2. In a device of the class described, the combination of a front head, a closure plate secured to the outer end of said front head, a working implement movable within said front head and extensible through said closure plate, settable means supported by said closure plate and movable relatively thereto for controlling movement of said working implement within said front head, and a projection on said settable means cooperative with said closure plate to restrict said means to an oscillating movement between positive limits defined by said closure plate, said projection extending through said closure plate in position to be grasped manually to effect relative movement of said settable means.

3. In a device of the class described, the combination of a front head, a retaining ring supported for independent radjustment adjacent the outer Aend of said front head and having a central bore through which access may be had to the interior of said front head, a pair of intersecting slots formed in the inner periphery of said retaining ring, said slots being disposed at right angles with respect to each other, a working implement adapted to be inserted into said front head through a selected one of said intersecting slots, said working implement having a maximum width greater than the diameter of said central bore and a portion of reduced width less than the diameter of said central bore whereby said retaining ring may be moved relatively to said working implement when the reduced portion of said implement is brought to registry with said ring to lock said implement within the front head, and means for holding said retaining ring yieldingly in a set position of adjustment in which said working implement is locked within said front head irrespective of the slot through which it is inserted therein.

4. In a device of the class described, the combination of a front head, a closure plate secured to the outer end of said front head and having a central bore through which access may be had to the interior of said front head, a retaining ring supported by said closure plate for movement independently thereof and having a central bore registering with the central bore in said closure plate, a pair of intersecting slots formed in the inner periphery of said retaining ring, said slots being disposed at right angles with respect to each other, a vworking implement adapted to be inserted into said front head through a selected one of said intersecting slots, said working implement having a maximum width greater than the diameter of the central bore of said ring and a portion of reduced width less than the diameter of said central bore whereby said retaining ring may be moved relatively to said working implement when the reduced portion of said implement is brought to registry with said ring to lock said implement within the front head, and a projection on said retaining ring cooperative with said closure plate to restrict said ring to an oscillating movement between positive limits defined by said closure plate, said retaining ring acting in one limit of movement to lock said working implement within said front head irrespective of the retaining ring slot through which it is inserted therein.

5. In a device of the class described, the combination of a front head, a closure plate secured to the outer end of said iront head and having a central bore through which access may be had to the interior of said front head, a retaining ring supported by said closure plate for movement independently thereof and having a central bore registering with the'central bore in said closure plate, a pair of intersecting slots formed in the inner periphery of said retaining ring, said slots being disposed at right angles with respect to each other, a iiat working implement of substantially rectangular cross-section adapted t0 be inserted into said front head through a se1ected one of said intersecting slots and adapted to be positioned to receive impacts from a hammer piston, a chuck having a diametrical slot receiving said working implement, said chuck being the reduced portion of said implement is brought to registry with said ring to 'lock said implement Within the front head, and a projection on said retaining ring cooperative with said closure plateto l'restrict said ring to an oscillating movement between positive limits defined by said closure plate, said retaining ring acting in one limit of movement to lock said Working implement Within said front head irrespective f the retaining ring i0 slot through which it is inserted therein.

MATTHEW OFARRELL. 

